PLATE LI. 



Figures magnified 500 diameters. 



PAGE. 



Figs. 1, 2. STAURASTRUM BREVISPIKA, Var., front and end views, . 134 



" 3, 4. " Var. inerme, . . 134 



" 5, 6. STAURASTRUM DICKIEI, two aspects, . . .135 



" 7, 9, 10, 11. STAURASTRUM DEJECTUM, Var. convergens, . . 134 



Fig. 8. Var mucronatum, . . 134 



Figs. 12-14. STAURASTRUM TRIHEDRALE, in three aspects, . 136 



" 15, 16. STAURASTRUM ARISTIFERUM, .... 185 



" 17-22. STAURASTRUM DEJECTUM, four forms and a zygospore, 134 



" 23, 25. STAURASTRUM CUSPIDATUM, .... 135 



" 26, 27. STAURASTRUM LEWISII, front and end views, . . 135 



" 28, 29. STAURASTRUM TRIFIDUM, front and end views, . . 136 



" 30, 32 STAURASTRUM AVICULUM, .... 136 



" 33, 34. STAURASTRUM COMMUTATUM, . . . .136 



" 35, 36. STAURASTRUM KITCHELII, two views, . . . 165 



" 37-39. STAURASTRUM BRACHIATUM, .... 136 



" 40, 41 STAURASTRUM FURCATUM, a form of a variable species. 165 



